Telephone-exchange system.



F. R. MCBERTY.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED NOV.10, 1910.

it V 2 22 3w j M mmegtm F. R. MQBBRTY.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED NOV. 10, 1910.

Patented Sept. 8, 1914;

& SHEETSSHEBT 3.

P. R. McBERTY. TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED NOV. 10,1910.

FRANK R. MCBERTY, OF Ill'flill/V ROCHELLE, NEW YQRK, ASSIGNOR TC 'WfiIEER'I'J 1-1353"- LTIRIG GUMPANY, OF NEVlT 'YOEK,'N. SR, A CORPORATIQN, 01E ILLINQIS.

TELELPHGIBTfl'EXCI-IANGE SYSTEM.

icense.

v Specification of Letters Patent.

Application filed November 1Q, 1816. Serial No. 591,580.

r cemes Sept. s, leis,

' lines may be controlled and accomplished speedily and with precision.

The ohjcctlol my invention is to provide in a system involving mechanical switching apparatus. a controlling organization by which such mechanical. switching apparatus may be governed in its operation to esta'o-. lish the llcsiri' rl connection, which controlling organizaiion is in turn governed or set ratus by distant so-called sender apparatus ac,

cording to-thc designation of she desired,

line

A further object of my invention is to provide a system in which a secondary controlling organization may be adjusted or set in controlling condition by in pulses trausu'iittcd over long or short lines by a primary controller, and whereby such scooudary controller may he automatically and quickl associated with the line or appaassociated with the primary controller takcn for use.

A further object of my invention is to provide in a system involving mechanical switching apparatus adapted to operate and he controlled according to what is known as the revcrtivc impulse system of control, a secondar controlling organization adapted to he set by impulses received therein from a primary controller operated from a calling \line, and haviiig-becn so set to cooperate with such mechanical switching apparatus to accomplish through said apparatus the connection of the desired line.'

More particularly my invention involves a system including automatic switching apparatus, a primary sender mechanism adapt: cd to be manually set according to the designation of the line desired, and to transmit impulses in accordance with such designm lion, and a secondary controller adaplled 230.

he set or adjusted in response to the receipli of the impulses from such primary coutroller, and when so set and adjusted to corn trol the operation of the mechanical switching apparatus to produce the desired con.

nection, such secondary controlling apparatus being adapted to be autoinarically connected to the circuit of the primary controlling apparatus and to be disconnected therefrom upon the completion of the dc:-

, sired connection.

vly invention is shown as appliec r full automatic telephone exchange system.

but it should be understood that While i particularly adapted to and has been found especially efficient in connection with full automatic systems, my invention is not confined to use in such systems, but may be edvantagcou sly used in connection with any or all systems involving" mechanical switching apparatus which must be rapidly and accurately controlled. 1 have furthermore shown my invention in connection with mechanical switching apparatus of a particular form,

but it will be apparent that it is not confined,

to use in connection withlsw'itching apparatus of this type, but may be used'with any switching apparatus of suitable or convenient structure and arrangement. Furthermore, While the mechanical switching apps; ratus inconnectlon with which have shown.

my vinvention is controlled according to what is known as the re crtiye impulse sy tem of control, it must be understood that my invention is not limited to such system,

of control, but may, if desired, be used in connection with switching apparatus de.-- signed to be controlled by impulses received from the controlling apparatus, as will he hereinafter pointed ou ill? My invention also includes certain details,

of the construction and OIgJLIIlZZL-ClOH oil-the circuits and apparatus involved in my inipro ved controlling system-by which the foregoing results and operations, and other. ref,v 'sults and operations incidental to the nroper i and expeditious accomplishment of t 'e inter-connection of telephone lines and trunk 'linesi'n systems of the character indicated may he best accomplished.

In the drawings, Figures 1, 2, 3 and when placed together form a single diagram illustratingdiagrammatically the circuits and apparatus involved 111 the full automatic exchange system comprising in'p'art a systerm of control in accordance with my invention; the lines which extend to the edge of each sheet being continued on the neighboring sheet. The proper arrangement of the sheets for viewing the system a whole is made by placing Fig. 2 to the right of Fig. 1, Fig. 3 immediately below Fig. 2, and Fig. 4 immediately to the right of Fig. 2. v

Like parts are ref rred to by the same reference characters throughout the specification.

Line fimZcrs.A part of the apparatus involved in the preferred form of my inven tion and as shown in the drawings herein comprises a series of line finders such as the one shown to the left of Fig. 2 on the upper part thereof. These line finders may be of any usual or convenient construction, but each comprises preferably a set of three brushes adapted to be rotated to sweep over any desired and convenient number of sets of line terminals, each such set of line terminals comprising three terminals, that is, two line terminals and a test terminal. The three brushes referred to may be driven in any preferred manner, but on the drawing they are shown as driven by the power magnet 253. This power, magnet when energized will cause the rotation of the brushes over the terminals by means of an electromagnetic clutch such as is well known to the art and therefore need not be further described. So long as the power magnet is energized the brushes will move over the sets of terminals of the various lines until they come in contact with the terminals of the desired -or calling line when, in a manner to behereinafter described, the power magnet will be deenergized and the brushes will stop in contact with the terminals of such line. It should be further noted that the test brush as indicated on Fig. made of elongated form so that it will make. contact with the test terminal of one set of terminals before breaking contact with the test terminal of the preceding set of terminals. The line brushes, however, will not bridge from .one line terminal to the next. It will be furthermore noted that these line finders when not in use may rest upon the terminals of a line with which they were last operatively connected since in the normal condition'of the apparatus associated therewith the various brushes are connected in no way to any, electrical potential or ground and therefore cannot in any way atlect the line on the terminals of which they are resting.

Sequence s wz'tohcsr-The local controlling circuits associated with the various parts of the exchangesystem disclosed herein, which local controlling circuits must be established in definite order at successive stages of the operation of such system" to' bring into service the different devices or parts they mousse are required, are in the present embodiment of my invention established by automatic electromechanical switching appliances which are termed sequence switches. As will be noted by reference to the drawing, there is a sequence. switch associated with the primary finder apparatus and the first selector, a sequence switch associated with the secondary controller apparatus, and sequence switch associated with the final selector. Each of these sequence switches conists in its elements of a movable switch operating member, a number of circuit changers or contact devices actuated in sequence as said member is moved from one position to another, an electromagnet and a motor mechanism operated or controlled by said magnet for. advancing said movable member through its successive positions.

The sequence switch may control any desired sequence of operation, whether of the same or difierent devices. In each position to which this movable member is advanced, a circuit is established whereby given operation of the device or devices under control, is made possible, and at the same time another circuit is established whereby the motor mechanism of the sequence switch may be actuated automatically when such operation of the device or devices under control has been completed; so that as each op eration takes place the sequence switch will be automatically moved to the next position, in which position a new operation or another stage of the same operation will be brought about and so on. Finally the sequence switch establishes a condition whereby the-apparatus under control. is returned to its normal condition, and also establishes a circuit whereby the sequence switch will be returned to its normal position. In each such position, the apparatus and its associated sequence switch may be and are preterably so related that local reciprocal controlling circuits will be progressively established by said devices in their operation, in such a manner that when a normal operation of either is started both devices will be progressively carried through a complete cycle of operations which may be controlled and checked at different stages through the agency of energizing circuits established by some other portion of the apparatus for this purpose, but which unless so checked will terminate in the automatic return of both the sequence switch and its associated apparatus to normal condition. in case of a failure of current in such checking or controlling circuit, even immediately after a se quence switch and its associated apparatus have started in operation, such sequence switch and apparatus cannot become permanently displaced or stalled in an oii normal condition but will complete their cycle of operations and. be positively returned to 'As these special contacts.

normal under control of circuits which are purely local.

- In the circuit diagram herein illustrating my invention, the switch springs of the sequence switches are not shown in their 'actual arrangement, but are so located as to give the clearest arrangement of circuits.-

Furthermore, the operating cams are not shown. The positions of the rotary element of each sequence switch, in which any of its contacts are closed, are indicated by nu1nhers placed adjacent to such contacts, each contact, except the special contacts which switch contact is the same as the hundreds digit of the reference character applied to the sequence switch of which it forms a part. It will furthermore be observed that the sequence switch contacts on any sheet are all controlled and operated by the secplience switch power apparatus shown upon t e same sheet; for example, all sequence switch contacts the hundreds digit of whose reference character is 2, form a part of the sequence switch 201 which is shown upon the same sh'eet.

Each sequence switch has, however, as has been before noted, a special contact governing the local circuit of its motor magnet.

, which are represented by the contacts 202, 302 and 402 on the respective sequence switches 201,301 and 491, are closed only while the rotary element of the sequence switch is in transit from one stopping position to the next, the numbers are placed on the side of the switch lever opposite from the contact and indicate the positions in which such contact is open, such Icontac't being closed at all times while the rotary element is in transit between the positions indicated by the numbers. The numbers adjacent to these special contacts of the various sequence switches indicat'e,therefore, the only positions in which their associated sequence switches are arranged to stop. Since, however, sequence switches of the character described are well known to the art, the particular structure andarranges ment of the form used and shown in the pre- 'ferred form of my invention need not be particularly described and any form thereof which may be suitable or convenient may be used.

' Selector switckes.l n the form of automatic switch shown in Fig. 4., the switch carriage or movable element is provided with e number of-sets of multiple brushes, any particular set of which may be selectedfor service and the switch carriage then advanced, over a series of sets of line terminals until the selected brushes are brought into engagement with the terminals of a desired line. i

The switch carriage or brush carrying member is of the rotary type, the frame 21 of which is mounted upon a central standard or shaft 22. At the outer end otthe frame a number of sets of contact brushes 23, 24-, 25 are pivotallymounted upon but insulated from a rod 26, and from each other, in position to sweep over sets of line terminals 27, 28, 29. The brushes have inwardly eX- tending arms 30, bearing against which, one for each brush, are springs 31. Latches 32 one for each set of three brushes, are pivotally mounted upon a rod 36 and arranged to normally hold the brushes from being rocked outwardly into line with the stationary terminals. Bearing against the inner ends of the latches are springs 34: which hold the latches firmly against a stop rod 33. This stop rod 33 serves to prevent the latches from being moved forward too far after the brushes have been released. A stop bar 35 serves to limit the outward movement of the brushes when the latches are withdrawn.

The latches 32 and stop bar are of insulating material so that the circuits connected with the brushes will not be crossed thereby. The springs 31 make electrical connection with the brushes ;-they are of sheet metal and form the teeth of combs which connect corresponding brushes in the several sets in multiple. Suitable wire clip terminals 37, 38 and 39 are provided for the circuit connections to the springs and brushes.

As the brush carriage is rotated to cause the brushes to sweep over the fixed terminals, the latches first pass by a tripping device or brush selector, by which any desired set of brushes may be released and caused to swing outwardly. This tripping device comprises a shaft 40 provided with radially extending fingers 41 arranged spirally about the surface of the shaft. Thisshaft is adapted by mechanism, to be ycsently described, to be rotated so as to )ring the fingers one after another into the line of travel of the several latches on the brush carriage. Only one set of brushes is intended to be released in a given operation. The shaft is first rotated to bring a particular finger into position to engage the latch in the same level therewith and thenthe brush carriage is rotated. In passing, the outward edge of this latch strikes the end of the finger, allowing one set of three brushes to be released. Continued movement of the brush carriage brings the selected set of brushes into engagement. with the rows of stationary terminals in the same level therewith, these brushes trailing over the terminals and making contact therewith in passing. The

brush carriage is finally cause to stop withthe selected brushes in contact with some one set of stationary terminals. The other brushes not being released, are held out or" contact with the terminals over which they pass. A further movement of the brush carriage in the same direction of rotation will carry the brushes over a restoring roller 69, which may be pivoted to the frame and which engages the Joe ends of the released set, causing them to be pushed back into their normal latched position. After male ing a full revolution, the brush carriage is brought to rest in its normal position again.

The brush selector and the brush carriage of this switch mechanism are arranged to e moved one following the other by suitable motor mechanisms which will impart to each a continuous movement. In order that the successive positions taken by each movable member may he stepped oil or measured, each is provided with an interrupter deice adapted to make and break a contact in the controlling circuit as the moving member passes the several positions at which it may be desired to Cl use said member to stop. Thisfl interrupter device for the brush carriage comprises a pair of contact springs 48, 1 9 seciired to, the shaft 22, but insulated from said sha tt andirom each other. T he outer ends of these springs are engaged by inwardly extending arms all and of a pair of levers &2, L3, which are piv otally mounted upon the rod 26. These levers l2 and l are insulated from the springs 48 and it) by small insulating buttons at the ends oi? the-arms all and .5, but are uninsulatecl from the rod 26 which is connected to ground through the frame of the selector mechanisut in the u'iovement of the brush carria c a roller 51 on the free end of the lcrer 42 engages the teeth 53 of a can). plate 50, the roller engaging each teeth as the brushes are trarersiug the space octween the successive terminals and dropping into the notches between the teeth as the brushes are centrally located in contact with said terminals. While the roller 51 is riding over the teeth of the plate 5.30 the curved end of the lever is in engagement with the smooth edge of that plate A relative movement of the lovers and i3 is thus obtained by their engagement with the edges of plate and this movement is, therefore, indepenocnt of slight variations in the radial distance between the plate and the axis ot-movcment ofthe brush carriagel By this construction the duration of contact between the interrupter sprinp's 4S and 4-9 is made uniform in the movement oil the brush carriage, each malre and each lireal; correspond ing to particular position of the brnshes with respect to the terminals.

In the normal position of the switch mechanism, the lovers l-zland rest in a tact recess or" a normal plate 46. Th entering edge of th s plate is covered with insulating material in order to prevent the free ends of the levers and s3 from making electrical contact with the plate 46 before reaching the full normal position in which the ends of the levers drop into the The interrupter for the brush selector comprises an arm pivoted to the frame at 57, engaging at its free end a toothed wheel or cam 58 which rotates with the shaft 450. This arm. 56 is adapted in the rotation of the shaft to engage two contacts 59 and co. These contacts may he springs, the free ends only of which are shown in the draW- ing. in its normal position the free end of the arm 56 lies in a notch of the cam 58 which is deep enoughto insure an open connection with contact 59. When the shaft is away from its normal position, however, connection is made continuously with con- The connection with contact 60 is intermittent, this contact being made when the arm 56 is lifted by each tooth of the cam. There are as many teeth on the cam as there are fingers on the spindle 40 and therefore as many as there are sets of brushes.

The motor mechanism for causing rotation of the brush carriage comprises an annular iron friction disk 61 flexibly mounted at the lower end or the spindle 22, an electromagne't 82 which may he'fixod in any suitable manner to the'frame, and aeolistantly rotating; shaft 63 carrying an iron driving roller The disk 61, roller 64 and that part of the shaft 63 which extends through the center of the electromagnet 62 forn'i the magnetic circuit of the electromagnct G2. -When therefore current is passed through the winding of the magnet, the roller (ll attracts the disk 61 and causes the latter to rotate by frictional contact therewith. A holding clectromagnet 65 having a pole re 66 extending upwardly beneath the dish 61 is adapted when current is passed through its winding to engage the disk and hold it from movement. The power shaft is extended as shown in the drawing to carry ailcxibly mooutcd driving dis-l1 To, which is adapted to engage aroller 67 carried by the spindle An electromagne-t (38 controls the engagement of disk 70 and roller (37 in the same manner that the elect o'magnct 62 controls the engagement of '6, sir (El and roller These devices are in fact electromagnetic clutches, one to cause movemcntor" the brush carriage and the other to cause. movement of the brush selector he complete selector switch mechanism is not shown in the drawing, but the elcments thereof appear in. t eir proper relation to one another as to make clear the manner in which the ism operates to terminals. ....l't'l)ll1(l the roller one tooth or notch and interconnect lines. There may he as many sets of brushes and stationary terminals as desired. For example, the switch mechanism may, as a whole, have ten sets of three,

brushes each and two'hundred sets of fixed terminals arranged in ten'levels of twenty sets each. For simplicity in the diagram there are shown only two sets of brushes, the 8th and 9th counting from the top down, and six sets of stationary terminals in two levels corres ionding" to the two sets of brushes shown.

The selector switch structure shown in Fig. 2 is precisely the some as that shown in Fig. with the exception of the interrupter apparatus shown at the top thereof, the structure and operation 0:5 which is as f0llows:

In the normal position of the brush carriage, as shown. in Fig. 2, a pair of levers 82, c2 engage at their free ends a normal stop plate d6. At the end or lever 82 is a roller 71 which lies in a recess of plate i6, and at the end of lever 83 is a right angle extension arm 72 which makes electrical contact with said plate 46. A coil spring 86, acting upon an inwardly extending arm H-l. serves to press the rol er 71 with considerable force against plate &6 and thereby holds the brush carriage securely in its normal position. A flat spring 73 engages an inwardly extending; arm of the lever and serves to press this lever outwardly but with im'co than that of the coil spring 56. The spring 73 also makes electrical contact with lever 83; it is secured to but insulated from the shaft 22 of the brush carriage anal terminates in a wire clip 87.

As the brush carriage is moved to carry the brushes over the stationary terminals, the roller 71 and the extension arm T2 en- ;ragc the teeth of a cam plate 90. The roller 71 rides over the teeth while the brushes are passing between terminals and drops into a notch as any rclaiscd set of brushes is centrully locutcd in direct contact with a set of The extension arm 72 follows likewise engages a tooth as the brushes are passing between successive terminals. it

passz-s through. the space between teeth, liowoi'cr without touching the plate 90, as the released set of brushes is centrally located in contact with the terminals. The stop bar 33 engages the inwardly extending arm 85 just as it docs the arms 30 of the brushes and thus prevents the extension arm T2 of the lever 83 from touchingthe bottom oi the notches betwcen'tho teeth of plate 90, but permitting said arm 72 to touch and make contact with the top of t e teeth. 'llic tooth and notches of plate are so spaced and arranged with respect to the contact lcver 83 that the extension arm will not lu-calc'coutact with a tooth of plate 90 over the notches on such dial.

until after the brushes make contact with the stationary terminals and the roller 71 is ready to drop into a notch. lhe circuit arangement. as will presently appear, is such that the motive power for driving the brush carriage cannot be out ch until the Contact is thus broken between lever 83 and plate 90 and therefore not until the brushes are in to the art and will not therefore be described in detail, comprises a series of circuit brealc ing dials and a master switch. The circuit breaking dials or digit dials, of which there are three shown, are adapted to be manually set by the subscriber to indicate when taken together the designation of the desired line. i /lien such dials have been set a power lever, not shown will he operated to supply power for operating such digit dials. The first oi? the digit dials, herein shown as the hundreds dial will then start to rotate and in such rotation will open and close the impulse sending circuit as the contact lever shown in association with such dial rides The number of limes that the impulse sending circuit will be opened will depend upon the posilion of the dial and" the cirhuit will be opened briefly a varying number of times according to the set position of he dial and then once opened for z comparatively longer period. The dial when it reaches its normal position will then stop. is soon as the hundreds dial has reached 5 tion the tens digit dial will bcgin to move breaking the circuit briefly for a varying number of times ucpording to the set posi Lion oi'- the dial and then breaking the circuit for a comparatively longer period once just before reaching normal position. As soon as the tens dial comes to rest in its normal position the units dial will operate in a precisely similar manner.

The master switch above referred to may be and is preferably controlled by the power lever which, as is above noted, is operated to furnish power for the operation of the respective digit dials. The first movement of the power lci'er will. operate the master switch in such a manner that it will include the impulse sending circuit which passes through the various contact devices of the digit dials in the line circuit of the associalcd telephone line. The structure of this switch, however, is so designed that the Q11- s normal posicuit will be closed through the impulse sending circuit before the line conductor is opened as is plainly indicated upon the dra *ings.

It should be oliwserved that the digit numerals are placed upon the digit dials in such positions that the number of impulses sent over the impulse sending circuit is the tfiOlitPltlIlQllt of such numerals. That is to say, if one oi? the di ;:it dials is set for the No. 8, two impulses will be sent over the impulse sending circuit, one short and one long. Similarly, it one of the digit/dials is set at zero, ten ianuilses will be sent over the impulse sending circuit, nine of such impulses being short and the last one long. The object of this arrangement will clearly appear in the description of the operation of the system embodying my invention and depends in a word on the fact that the register senders herein shown operate upon what is known as the complementary system of control.

In connection with the operation of the subscribers substation apparatus including his sensor or primary controller, the instructions given such subscriber for the proper operation or the system require that he should in making a call first remove his re ceiver from its switch hook and then proceed to set the sender or primary controller mechanism to the designation of the desired line. Thenhaving set his primary controller, he will operate the power lever above referred to. During the interval between the removal of his receiver from its switch hook and the operation of the power lever, ample time will elapse for the connection to his line of a finder device and of a registersender or secondary controller her inafter to he described.

t should be further noted that due to the presence of the master switch, the movement of the digit dials by the subscriber in setting them will not in any way ali'ect the line circuit and no impulses will be sent to the central station during such movement. \Vhen, however, the master switch is operated, the digit dials will move one after another and t*ansmit impulses to the central station, as'

has been hereinbetorc referred to and as will be hereinafter more fully described.

Register sender or secondary controller.- The secondary controller shown herein, of which there will be two associated with each group of lines and connecting circuits and whose association with a connecting circuit taken For use will suliiciently appear in the description of the operation of the system embodying my invention, comprises a slow release relay indicated at 321. a stepping relay 32:2, a SOqtlOlltB switch 301 and three register-scmlers Ill-l, 336i and 381. OF this apparatus the register-senders need only he described in detail. Each of these registergized.

senders thc one indicated at 34-1, for example, which will be hereinafter referred to as the hundreds register-sender, pal-takes somewhat of the nature of a sequence switch; that is to say, it comprises a shaft 34-9 which, like the shaft of the sequence switch hereinbe'tore described, is rotated when the register sender magnet 350 is ener- On this shaft are located the three switching operating disks 3&2, 345 and 3&7.

Considering first the switch operating disk EH5 it. will be observed that the periphcry of this disk is divided into twenty-two parts. Each of twenty-one of these parts is recessed in such a manner that the contact arm of the switch 346, when it rests in such recesses, will not make contact with its back contact, but when passing from one recess to the next will so ride upon the periphery of the disk that it will make contact with such back contact. The one remaining portion of the periphery of this disk which is not recessed is, as shown, immediately adjacent to the recess in which the contact arm 346 is designed to rest when the registersender is in its normal position. The contact arm 3+6 associated with this disk 345 is similar in its operation to the special contacts 202, 302 and -Lt02 heretofore referred to and well known to the art, such contact arm being so connected to the operating magnet 350 of the hundreds register-sender that when the shaft 3-H) is moved out of a position in which the contact arm 346 rests in a recess, its movement will continue until the contact arm 34G again rests in a recess of the disk 3&5.

The disk 342 of the hundreds registersender is provided with eleven recesses similar to those on the disk 3&3 and located with relation to the shaft correspondingly with the alternate recesses upon the disk 345. A contact arm operating contacts 3&3 and 344: is adapted to ride over the periphery of this disk and when resting in one of the recesses thereon to close the contacts 344 and when resting upon the periphery of such disk between two of the recesses thereon to close the contact 343.

The third disk 347 of the hundreds rec'- istcr is provided with but one recess which is elongated and is located with relation to the shaft 349 to correspond with the unrecessed portions of the disk 34-5. This disk also has a contact arm cotiperating therewith and adapted toride over its periphery, such contact arm maintaining the contacts 348 closed except when it rests in the elongated recess above referred to. t

T he hundreds register is adapted to Stand normally in the position in which it is sliown in Fig. 3 and will be moved from such position and restored to its normal position in the manner which will be hereinafter described in the description of the ope 'ation moves his receiver from its switch hook,

which act closes a circuit from the battery 149 through the armature 111 and its back contact of the multiple cut-oil relay 112, armature 113 and its back contact of the cutoff relay 114, line conductor 101, the now closed switch hook 115 of the subscribers apparatus 110, line conductor 102, master switclr 171, line conductor 102, back contact and armature 117 of the cutoff relay 114,

back contact and armature 118 of the multiple cuto'fi relay 112, line relay 119 to ground and back to battery. The closure of this circuit energizes the line relay 119 which attracts its armature and closes a circuit from ,the battery 149 at its middle or neutral point, through the cutoff relay 114, front contact and armature of the line relay 119, starting relay 251 to ground and back to battery. Current from battery 149 alone, through relays 114 and 251 in series, is insufficient to energize relay 114. It is only when current from battery 249, in Fig. 2, is

added to the current from battery 149, that relay 114 will be energized, as will be hereinafter described. cult energizes the starting relay 251, whlch controls theprimary selector sequence switch starting circuit and is common to the lines rof the group of lines of which the'calling line is one. The energization of tlns starting relay closes a circuit from battery through the primary sequence switch 201, sequence switch contact 203, sequence switch contact 204, sequence switch contact 505 of the first connectingcircuit and primary selector common to this gi-oup, which at this time is assumedto bebusy, front. contact and armature of the starting relay 251 to ground and back to battery.

lietore describing the operation of the priuiaiw' sequence switch shown in response to the closure of the circuit just traccd, attention is directed to the arrangement of this circuit whereby the first idle connecting cir uit and its associated selector apparatus will be picldd up and operated upon the closure of the starting relay 251. This circuit normally is closed to the first primary sequencc switch through the sequence switch contact 501 of such sequence switch. \Yhcn,

however, this sequence switch moves from its idle position it opens the sequence-switch contact 501 and closes 111 its third position The closure of this cir-' the sequence switch contact 505 so that the starting circuit is extended to the second primary sequenceswitch so long'as it is idle, through the sequence switch contact 505 of the first primary sequence switch, and the sequence switch contact 204 of the second primary sequence switch. When new the second primary sequence-switch reaches its third position in its operation, it has opened the sequence switch contact 204 and has closed the starting circuit to the third primary sequence switch and its associated apparatus through-the sequence switch contact 238. In this way the first idle primary sequence switch will be picked up upon the energization of the starting relay 251. It

will be furthermore observed in this connection that in the operation of the exchange each primary sequence switch when oncev started will rapidly pass to its third position and-no appreciable delay can occur owing to the circuitbeing open in the second position of any primary sequence swit h.

Theprimary sequence switch 201 having been energized by the starting circuit, as traced moves into its second position, in this position closing a circuit for the finder control relay 252 so long as the brushes of the finder rest upon the terminals of an idle or non-calling line, which circuit may be traced from battery 149 at its middle or neutral point through the cutoff relay 114, test conductor 103, test brush of the finder, sequence switch contact 205, finder control rela 252 to ground and back to battery. It s ould be ex lained at this time that current througi the circuit traced wili energize the finder control relay 252 only so long as there is no shunt to round upon such circuit." It should be fii irther noted that the current through the circuit traced will not energize the cutoff relay 114. When, however, the test brush rests upon the test con ductor 103 to which there is aiready connected a circuit to ground through the arma .ture and front contact of a line relay 119,

insufiicient current will pass,- through this finder control relay 252 and such relay will be deiinergized.

As will be hereinafter ointed out, the finder control relay will nd full battery potential for its energization on the test terminal of every linewhethcr idle or busy, except calling lines. Upon the energization of the finder control relay armature and closes a circuit from battery through the finder power magnet 3, sequence switch contact 206, frontcontact and armature of the finder control relay 252 to ground and back to battery. The energization of the finder power magnet 253- will cause the various brushes of the finder to rotate to make contact with the sets of terminals of the various lines terminating in this particular finder. It will be recalled 252 it attracts its' will he maintained and the power magnet therefor energized so long as the finder brushes are in contact with the tern'iiuals of idle or non-calling lines. When, however, the finder brushes come in contact with the terminals of a line the line relay 119 of which is eicr izcd, current will pa s throu h relayto maintain it cuei will retract its armature opening cuit of the power magnet 253, there. U stopping the finder brushes in contact. the terminals of the calling line and also closing a circuit for the prin'iary sequence switch through the sequence switch contact 207 and the hack contact and armature of such relay 252. The primary sequence switch now moves into its third position.

lVhile the primary sequence switch was passing from its second to its third position it caused a momentary closure of the quence switch contact 208 this closure heing indicated upon the drawings by the characters 21 adjacent the said contact. The closure of this sequence vitch contact was for the purpose cit-testing the busy r idle condition of the first re tOP-SJl'ltliil or secondary controller associated with the group of connecting circuits of which the circuit shown is one. For the time being we will assume thatthc first secondary controller so tested was idle and that therefore 'no change tool; place due to the closure of test conch tor of the line with which the find hrushcs are now in contact which will nnilte such test conductor of sul'liciei'itly {h potentia to .u'iaintain energized the tin-oer control relay of any other finders which should pass (we-r the tern'iinals of this line. This will make the line test non-calling. The closure of the sequence switch contact 2 has tiu'thermoro placed sufficient hat-tern n circuit to cner: giro the cutoff rel-a; ill it being observed that'- in the circuit -t this cutoti' relay the hadterics 1&9 and 2t!) arc of the same 7olaritv. The cutotl relay ll 'v will tl'ieretore pull up immmliaicly that tic primary se ,ueucc switch reaches its tl ittl p e s1tion, and will by the attraction of i u uturcs it?) and 117 open the circuit of the line relay 119 which in turn will by the retraction of its armature open the c :cuit ot the starting relay .251. The eucrgizaticn of the cutoll relay lll has furthermore, by the attraction of its arnniturc 120 closed a circuit for the cutol'i' relay 112 which will make this line test busy at all of the linal selectors in which it appears as will he hereinafter explained.

The impulse circuit over which the impulses from the -hoary controller or sender at the suhscriher station will be received and which now established may be traced follows:Froin battery through the secondary controller sequence switch contact 303 t tor Sol, armature 25G 01 the relay 1, primary sequence switch contact Ell, conductor 1G2, master switch 171, which is a vet unoperated, conductor 102, receiver swi :n hook 115, conductor 101, sequence switch contact 210, armature 257 of the relay conductor 3- 2, stepping relay 322, slow release switchi relay 321, contacts 3 1 8, i 68 and 388, which are closed in the normal 9 J position of the register-senders, sequence ,witch contact 31}. to ground and hack to ii atteryi The closure of this circuit will energize the stepping relay 322 and the slow release relay 32L This euergixatiou of the stepping relay 522 is witluuu; effect at; this time, but the slow release relay 32L by the attraction of its armature has closed a circuit for the secondary controller sequence switch 301 from battery through such sequencc switch, sequence switch contact 30- trout contact and armature of the slow re lease relay 321 to ground and back to battcry. The secondary controller sequence switch now moves into its second position closingthe sequence switch contact 307 to place a busy guard upon this secondary controller and also closing the sequence switch contacts 305 and 306 to prepare the secondary controller for the receipt of the impulses from the suhscrihers station.

ll'hen now the subscriber by the operation of the power lever referrel to starts the movement of the various digits dials 172, 17sand 176, the master switch 171 is operated so that instead of the two portions of the conductor 10) licing directly connectto say, the end of the movable por tion of the switch 173 is resting between the teeth on that portion of the digits dial 172 indicated at (J, the end of the movable portion of the sw tch 175 is resting between the teeth on that portion oi the digits dial lT'iindicated at Q, and the end of the movable portion of the switch 177 is resting he c ooses tween the teeth on that portionot the digits dial 176 indicated at 9. When therefore upon the operation of the power lever and the .muster switch 171 the hundreds digits magnetof the hundreds registersender 341, sequence switch contact 306,'c'cntacts 344-, back contact and armature of the stepping relay 322 to ground and back to lost tery. The hundreds register-sender now moves the disks 3-42, 345 audfi'? in s clockwise direction until the movable portion of the contacts 346 rest in the-second recess upon the disk .3415. It will be noted that immediately the hundreds register-sender begun to move the contacts Eldest-were opened and tho-contacts 343 were closed, the movemerit of the register-sender into the proper position being accomplished, by the closure of the switch 8426. Before the slow release relay 3'21 ccnretrsct-its armature, the contscts 173 are again closed hythe movement;

of the hundreds digits 1diel 17'2 and -:the

stepping rclsy322 is logsinenergized. This;

causes a renewed ener zution of .the power magnet. of the hundre SittglShGF-fififld5ir 34.1,; this time throughithe contects l w'lucheree I10.W,-1l059d. The hundreds registemsenderl thereupon :moves s'sccond step openmg'thel contacts 33:3 and closing the contacts 34 i; ondcoming to rest with the movcblezpor-g tion of the switch in the third recess; u'ponuthe disk The continued move ment of the hundreds digits dial 172 sgzun opens and closes after .u brief'interval the impulse circuit, and in the manner gust-doscribed the L hundreds register-sender is moved until the movsble portion of the switch 13% is in the fitth reeess'upon the disk I345. The third brief opening of the switch 173 due to the continuedmoyement of the hundreds digits dial 172 in s precisely similar manner brings the hundreds register sender into a position where the movable portion of the switch 346 rests in the seventh recess of the disk The continued movement of the hundreds digits dial now opens the switch 173 for a comparatively longer period. 'Upon the opening of the switch 173 the stepping relay 322- is denergized, and as before moves the hundreds register-sender one step so that the contacts 3441 are opened vand the contacts 243 are closed cndthe movable portion of theswitch 346 rests in the eighth recess of the disk 345. At this time, however, the :prolongedopening of the circuit which, it may heuiote'd,

than the openings heretofore described,

.causcsvthe release of the slow release switching relay 321 which retracts its armature and closes a circuit for the secondary controller sequence switch 301 through the sequenceswitch contact 305' and the backcontact and armature of the slow release relay. This starts the secondary controller sequence switch in motion which now, under ther-control of its specisl-contact302, moves until it reaches its fourth-position. It should be noted, however,,that the sequence -.s\witcl1 contact 306 is maintained closed in the third position ofthe secondary'control- .lerisequenceswitch, and the time relation-betweenthe movement of the hundreds digits dial 172,:the slow release relaiy 321 end' the sequence switch contact 301is such thatithe impulse sending circuit will beclosed-egcin after the long opening thereof before the secondary controller sequence switch *has passed through its third positiomthe,stop:- ping relay 322 being thereby energized and ,moving the hundreds register sender :34l1

.snother step by a circuit through the contacts'343 so that the movable portion the switch 346 'nowrests in the ninth recess is only long in the sense that it is longer upon-the disk 345. The sequence switchon coming into its fourth position will mowfind .s. circuit for itself closed throughfthe front contact and armature of the slow release reley 321 and the sequence switch-cohtact 804 and will therefore continue to snore until it reaches its'fifth position, hay-- ing opened the sequence switch contact 306 on'leaving the third position and closing the sequence switch contact 308 =on reschiii-g the fifth position.

iThe ihundre'ds digits dial having completed its movement, the tens digits dial will now begin to move. This dial in its move- ;ment will open thecircuit briefly seven times as is quite epparentond then once for acom- ,psra'tively longer period. These openings .end closures of tens'digits dial will drive the tens register-sender 361 sixteen steps and bring this register sender to rest with the mouable portion of the switch 366 in the seventeenth recess .upon the disk 865. It will be observed that the control of this tens-reg ister-sonder is alternately shifted :to :the

front and back contact of the stepping relay 322 by the-contacts 363 and36l in a manner precisely similar to the why inwh-ich the lay 321 isdecnongi-z'ed and a circuit established through its back contact and the :sequenceswitch contact 305 for the secondary controller sequence switch 301 to drive such longer-period, the slow release switching -res under thc coniroi 0. i's speinio its s nth sition, it rvcci that me cicsoz'c of the 1'" t thc cu i longer tooth s dial l "11 occur before 11. ltlfliii' scqi'cncc switch has position, cor ic'ung by 5116 ens qncncc switcl units digits dial a mo 'c. but since it I men the impulse and this for a comparalhis will cause the units '1. to move two steps and r-scndcr '10 rest with the swi i in the c disk i It will he also that the ccnt'roi has been shificd (/5 she coi'iiact '==c 1ui1:cd by the con- 2 i that inrihcrmorc zinc the sequcncc switch 111 inc 11111211 pills-c scm of thc uni qua? "3 switch c sequence switch (301 the relay conc broiler sequence .Witch and back to ca this circuit can mary sequence fourth posiiicn. nm' v SGquQllCQ so *1 contacts original Misc qucnce s mg the hne.

1 S11 DSC tion has ciso iacis $217., 218.

the secondary ccn comes intc i Wiich from if s bccn movcci The moicmcn; of i,

- on aim closcs {he scqiicncc switch coninct 2312 Li (ll-eds select n cciiico s1 thc prim 1: "O, swxnnc-e SW." qucncc switch com-ac I I the haw rchiy 2592, c):

ch 348 SWiiCil s1 switch coninct 312, cm

of relay 25%, scqucncc sm sequence switch contact hack 0 hatter). izcs 'thc lit in 322 and the slow rcic 321., which all them :m'csi It W111 be ob owing to the c2 troiicr sequence position,

nnis.

I Sch (or 213- ontac,

. which it will select cause the deenei'gization of the the interrupter con tact 306, a circuit for and armature of such line causes the primary sequence i to its fifth pgcsi f.

ie-nee suite A circuit is now c 233. through the brush 68,. sequence switch cents re of the the c icr its normal nos .on into set of selector brns w when ruptcr contacts 6@ s1 3lOSQL a a be plsceal on the selection contro at thesequenee switch Contact lay 3252 out will n? i energized. It will?) that the closure of th 6% smiths eonseque tien of the lfllltflll ti circuit inch s the slow em selecting spinille is metal tion to the next will not lie to cause the decnei; lease relay 321. flout. 322 upon its iienergizntion a; cuit through its back cents a, 34s and. the sequence switch, contact the power magnet of the liuntlrccls sender, which will thereupon in N opening the contacts 34;- entl clo contacts 343 and coming to rest movable portion of the switch. 3&8 tenth recess on the disk Wlicnn 1atch-selecting spindle reaches the 130:3: in which it will. select the first of se lector brushes, the shunt on the humliede selection controlling circuit is again ()QQHQL; the stepping relay 322 will be again gized and close through its front contact, the contacts 343 and the sequence switch conhe power magnet of the hundreds registec eucler This register-sender thereupon moves snothey g stc 0 enin the contacts 843, closin the contacts 344: and coming to rest 1 ltli the movable portion of the switch 3 3.6 in the eleventh recess upon the alislc For each subsequent closure of the contacts 69 lfrf, the rotation of the latch-selecting spinilie, theref0re, the stepping relay U22 will be briefly deenergizecl, moving the hundreds register sender a step in. e cloekv-Jise clii'cction 'mon its dencrgizatiou and another step upon its cnergimtion. This will continue until upon-the seventh closure of the shunting contacts fit: thehundrecls register-sender in moi ingf 'aises tlie moveble portion of the '1. conti'ollin 1 ac line p uni 4. the by u the F118 is nth positionl y cm Lrol ess on the disk 3 27, switch 348. Vlhcn, removed from the u' uil: by the opening (its (10, the line relay the shunt being renon controlling circuit S. This cleenerrelay 260 will close a seql'lencc switch. .?l1 contact and e the dc:

switcoin You: i llS circuit csteblishei act and the sequence vives the secondary con- "c switch into its fourteenth switct 348 is again .l liunoliecls register sender Il'liil oosition the hon diecls Se circuit closed,

re slow release els- 321, energized and attract my 260, the stepping cation of the without eitect this otion 02": the line relay at time except to l sure of a circuit for the cc switch through its back such sequence switch reaches However, the energizef the slow release relay 321 has closet. cuit for the secondary controller "sc switch 301 through its front contact c sequence switch Contact 304 which such sequence switch into its fifteenth l the register-sender is new selection. The hunection controlling circuit, howev 2.7,

lirough the sequence 1 switch contzic 29-0 and then through the sequence switch contact 225 and the front contact and structure of the line relay 260,

until the trunk hunting operation of the primary selector has 3 circuit has been ex em lGCl-OL no change time in the secondary lVlxen the primui y V being effected during this "231) eoinpleteclnntl the controller nqipurutus. znee switch reaches and to an iclle final semake contact Willi the nrst "enth position, ciru't is closctl from battery through the carriage rotary magnet 62 sequence switch contact 926, back contact rumture of the test r lay 261 to ground Jack to he oery. The brush cnrriac now move the portion of its movement pussin the brush latches by the i h-solecting spindle which, by its project finger, will cause the latch of the se- Ll set. of brushes to more and release 's brushes, so that come into coopcra re contact the sets of termiof t l i i o haul: of terminals in the selector. the further movement of the brush can mu e, the releesecl brushes will Wintling of the rlay "test seq ience center, '22? to ground hack to battery. will be noiec however, that if some other selector has just previously mode contsc with the terminals upon ll the the testtcrminnl 4 this selector e.- a other primary selectors in which it appears, it will prevent the energization of the test relays 262 and Bot of subsequent primary selectors which may later make Contact with the terminals associated with this particular final selector. Of course if the selector associated with this first set of terminals is in use, that is, its sequence switch is out of its first position there will he no buttery upon this test terminal and cons-e; (-Zillijf' there can he no cnergizzitiou of the tes relays and 201 {it this time. if therefl this test tcr minul tests husy. the relays cos {uni 251 will ronuiin unencrgizcil and the brush carriage will continue to more to bring the se" cte(l brushes into contact with the next tcrmin-sis oi their cooperating lirl oi terniinuls. The movement of the S\ ch carriage Will iliercfirre continue until the test brush of the SOlCCiUl set comes into contact with *1 test terminal to which the full potential hut-- tcrr is ctmuccttl. iinlimtiug' that the final selector to which it individual is iillc. As soon the test brush 25, therefore, comes in contact with such test terminal. the circuit will be closcil us lrcrctoiore traced to encrpgize the test relay 262, which thereupon zittincts armature nnil closes a low resistnnceicircuit through its lcit Winding to place the test condition heretofore referred. to upon the test terminal with which the test brush is now connected. The test relay 261, however, ill not he energized until, when selected brushes are centrally located sequence switch contactet of erminals it from battery through the sequence switch contact. 427, resistance e81, conductor 299; "the test brush of the selected set of brushes sequence switch cont ct 22S, rightj relay 261,

final sewill then be removed one such relay will be energized, attracting its armature and unmeclietely opening the circuit of the carriage rotary magnet 62 at its back contact. This movement of the armature of the test relay 261 has also closed at its front contact a circui't for the holding magnet through the and it circuit for the primary sequence switch 901 which will drive this sequence switch into its se; teentli position, the test relay 9S1 lii maintained energized through the locl'ecl-;r* mature of the test relay 262 While the pr mary sequence switch is passing through i s eleventh position.

As the prinisry sequence switch reaches its eleventh position it closes a restoring "circuit for the latch-selecting rotary magnet 68 through the sequence switch Contact 230, encl the spindle will. thereupon be moved again into normal position, stopping in such position on account of the orening of the oil-normal contacts 51 As the sequence switch came into its twelfth position the sequence switch contacts 231. and were elosecl and on leaving its in *lttli position he sequence switch contacts 2 19 and were opened. It may be noted at this point that the sequence switch contact 220 was opened when the primary sequence switch left its ninth position. A circuit is now close-(l and was closed before the hundreds selcclion controlling circuit was opened from battery through the armature 460 and its back contact of ihe battery control relay e39, through the iinnl line relay 1-74, final sequence switch contact 51, line conductor e91 select-or brush 23, primary sequence switch contact 231, sequence sw tch contact 217, armature 957 of the relay 259i, conductor 332, stepping relay slow release Jitching rcluy 321, switch 34-8, switch 36% switch 338, secondary controllersequence sr .ch contact 312, conductor S31, srinatrof the relay 2: primary sequence s contact 218, sequence switch con 3 selector brush 9i, line conductor sequence switch Contact 412, :irrmiture 25i anal its back coutuct of the batter control. relay 4-39 to ground and back to battery. This the tens selection controlling circuit. Upon the establishment of this tens selection controlling circuit the slow release relay 321 and the stcpning role will remain energized 11111 the linul line. relay lY-l will he energised to attract its nruniturc. Circuit will thereupon be established from battery through the final sequence switch 401, sequence switch contact 4.03 front contact, mill nrniuture of the filllll line relay 1. 4 to grountl and back to battery. The final sequence s itch now mores into its second position, opening the sequence switch contacts 403 and 427.

In this second position of the final sequence switch a circuit is established from battery through the latch-selecting rotary magnet sequence switch contact 404, front contact and armature of the line relay 474 to ground and back to battery, and the latchselecting spindle will begin to rotate, closing its off-normal contacts .59 and intermittently closing the contacts 60. lVhen the contacts are closed by the movement of the latchselecting spindle a shunt is placed upon the tens selection controlling circuit from ground through such contacts 60 and the sequence switch contact 423 which will cut ott' battery from that portion of the tens selection controlling circuit including the stepping relay 322 and the slow release relay 321, but will maintain the final line relay 474 energized. The stepping relay 322 will.

thereupon retract its armature and since the secondary controller sequence switch 301 is in its fifteenth position and the sequence switch contact 308 is closed, close a circuit through the contacts 364 to the power mag net of the tens register-sender to step such register sender one step in a clockwise direction, opening the contacts 364 and closing the contacts 363. in connection with the description of the operation of the primary selector, the shunt.

ing of the relays at the register-sender apparatus by the closure of the ground connection including the contacts 60 will not be of sufiiciently long duration to deenergize the slow release relay 321, and when the hitchselccting spindle has brought its first finger 41 into latch-operating position the shunt will be again opened and the stepping relay 322 again energized. The stepping relay 322 will thereupon retract its armature and cause a second step of the tens registen sender in a clockwise direction over a circuit including the contacts 363. It will be recalled that in setting the tens register-sender this register-sender was driven eight ste s due to the retraction of the armature of t e stepping relay .322 and eight steps due to the attraction of the armature of the'stepping relay 322. "When therefore tens selection control began, the movable portion of As has been before noted Therefore when the thefinal line relay 474 circuit is established for the final sequence switch 401 through the sequence switch contact 473, armature 443, and its back contact of the battery convtrol relay 439 and back contact and armature of the final line relay 474. The final sequence switch thereupon moves into its fifth osition and is ready for units selection.

lVhen the switch 368 opened as above de scribed, it remained open sufiiciently long for the slow release relay 321 to deenergize.

-Circuit was thertore closed for the secondary controller sequence switch 301 through the back contact of such relay and sequence switch contact 805 and secondary controller sequence switch was driven into its sixteenth position. As soon as the secondary controller sequence switch comes into its sinteenth position and the switch 368 has closedthe selection controlling circuit, which will now be termed the units selection controlling circuit, is again closed and the final. line relay 474, the stepping relay and the slow release relay 821 are again energized, the energization of the slow release relay 821 attracting its armature and by a circuit through its front Contact and a sequence switch contact 304 driving the secondary controller sequence switch into its seventeenth position. It may here be noted that this will occur by the time the final sequence switch is coming into its fifth position.

hen the final. sequence switch reaches its fifth position a circuit will be closed from I battery through the brushcarriuge rotary magnet 62 through the sequence switch con tact 4'77, front contact and armature of the final line relay 474 to ground and back to battery. The closure of this circuit will cause the brush carriage to move, in the first portion of its movement bringing the brush latches past the latch-selecting spindle and thereby causing the unlatching of the select ed set of brushes by the movement of their cooperating lat-ch when it contacted with.

the finger 41 upon the latch-selecting spindie. In the second portion of its movement, that is, as the selected brushes began to pass over the sets of terminals in their cooperat- -1ng bank of terminals the interrupter apparatus at the top of the selector will intermittently connect ground to the units selection controlling circuit through the sequence switch contact thereby before, shunting that portion of the units selection controlling circuit including the stcpping relay 322 and the slow release relay 321, but maintaining the final line relay 474 energized. This shunt will he placed on the units selecvtion controlling circuit once before the selected brushes come in contact with each of the respective sets of terminals in their cooperating bank of terminals. Each time that this shunt is placed upon the units selection controlling circuit the units regis- Iter-sender will he stepped one step over a stepimd ihe TEHW )oition s upcn .e nine mace at an 9 switch 001 new sequence switch conns sequence switch in 7 1e influence saqucnce opening f w ml n :ji' ueicc Ants-i1 12s anginanentiz 3710s 7 '1' 11011222. it cluse'i a circuit tin-magi: the sequence 0 1 w aci; 5 0 The closure of causes 86 pzinmry sequence awitcai to :1 ii; se'\-'-ent0enth p0siti0n and co in its eighteenth gosition. in 1mm; of file prinmry scgucnua W1 sequence switch contacts and 21' S5 opened. The coimectizig circuit with \vh this p 'inmry vecpmme swiich aim IIQQCi. new in 2111 7 1' WV a; \x i 211 90 ed a fun-3, my sequence m. have been 0p P 234,- have been c109 7 5 a que1'ic sWitch cmitncts EU a L i royed the selection ntr iiiin= ciosure of the contacts and picked the tailing circuit at the 190102 and of the 1: NO

t is p imriry sin 00h pzu'atus is now 1w will be further obse to be ilEFQiI12l sWi'r-h contacts 1.:

of the:

Referr V 1 final. selector and zssocihxx it will be rxraliad tin i, the switch 401 is now moving; fynm its, fifth ti) its ninth pos' ion. in this; mownwnt the desired line is "tested first in the, sixth and 1 seventh positions of 5111 i sm'guvnvc switch (in of the final Iii posiii e fies 1Q mmie from the the imtterv tin- M $32, I Hriil 25 (iii the y L Liv If the desired line i 2m m'dinn c-iinv and i. nut. busyit will be now '5 be upon the m tterv 1 4-9 "will be here noted that ilio polarity lost 123* lay normally stands in the posiiioi shown in Pig. l and when ouci ixcil by positive v more the multiple culroi' buttery upon the test tenninul of t-lieoii (l lino its ziifl'illltulcb move in a clockwise cli.i.'ec tiou, ramming to illQ 'poeutiou shown. upon the, (.ll "-iici'gizution of .AC rain The. Quergizution of those two test; you "i has closed :1 circuit for tho Lust iclsrw which may lie tlZlCQil jli'ion'i lui tciy tin-o such relay, front Contact Mi :1 :llilgllll: the lost relay 432, sequence su'izcli (ifillifiC'i- 4-07, buck coiilz ct and fiTEIlRlZLlFQ test icluy Salli to ground a (l in. The test i'oluy is the A and. cslublislics for itself u locking; cu" including i front OZllACL and alilliii llif and the sequence (:li ccuizict lic hero observed that the scumeucc cgmtucts 421 and 42: are :1 mixed lo. such a manner that the sequence 2W will be closed zlio pi'i. switch comes into its izentll positi fore the scqucnco switol. contact opened by the primary sequence 401 leuving its Illllilll positou 511 the sequence switch contact us the sequence switch comics into ils: c position before the sequence sswi ru coiitu. 41: is O'PGWJC by the sequence, sui"*l ing' its tenth msition and :-.-o O1). iiu icafiocl upon Clio (.lic Vlllgl ion of tho test we closed :1 circuit to rho cs5 its uriuutui'o and the testiholuy 43 .in shunt of test relay and K +231 wl'iicli circuit is of l resistance filuin the circuit in existed to the test brush aucl guard upon the test termiii with which the selected brcusli Contact in all the 5m solcc ills terminals of such lino up culled lino' wil now bel circuit of tho lino Mia; line and rcmoving all transmission circuit of such When the final sequence its ninth posi ion 11o furtu sin-y, in the misc a u' .1i1' .il lay has ulicucly been locz.

be maintained. locked up in 1* gll the PQlLLl'i f relay 432 ion of l i 1 (Ti) ill? f'G-il it fulfill its ninth posiiiig into the awoifi-h poolil .cquencs Switch 40]. again uerctoforo described as tho- 31 test relay :3 sequence switch contact operates in spite of circuit through the loft and closes a through like or Tom. 4535, 9 of be cost scqueiico swim:

luctor' 1G7 line 711, the cow conductor 101, Lcrminul. 2? (ill .eal brush s s-- comact 1A1, winding 451 o rol relay 4-30 to ground and The closure of this circuit.

ii w of; tl c ball at tho it on account at tho oubstw uss to onerremoves his i hook ho round the ion apps),-

in will now pass ici'gizcthc ringrcluy thereupon we; for its-elf 2 i'iacczfl from 14% of supivisoi'y ringing c011- ontuct and coco swi'ccli conbuttery.

completing lino uiul me iiiplcie from culled sub- Will be reculiccl the circuit through tlution coil it the primary sen; was closed ochre he final sequence This I. switch reached its twe fth position.

was eners Zing the final uni"; hue unit the arm: tures 460 and Q61 heir but-l: cont. the battery cons of i. re 1;; can This cnergizntion produced no eii'ect at that tune. llhen now however,

the final "eenth p uencc switch comes into its thirt'ion clue to vthe energization of so the called supervisory relay e28, this relay will be maintained energized in this position st as the switcn hook of the coiled sublong r renniins closed. On coming into the h position therefore the circuit will for the bsttery control reiuy ini the front contact and structure of trol relay- 439 will therefore be energized, in its encrg'izution opening the circuit of the final line relay =i-T 5 at nrnniturcs iiit) and The a'leenergizotion of the line relay iii therefore be substantially simulwith the cncrgizution oi the battery control relay 435), 11nd,, it may be here notctl upon the ilccnergization of the battery control relay 1839 the final line relay i'T i will be practically simultaneously energized. So long therefore as these two relays are not at the some time either in a cleenergized condition or at the some time in an energized contlitiou, the final sequence switch 401 will re? main in its thirteenth position. As above (lesc i ti n o'l' occl therefore, in the thirteenth posiii sequence switch the battery control is energized and the iinzrl line relay i s clenergizecl. Conrersetion will now into place.

it may be herei otcd that on coming into thirteenth position the finul. sequence ch closed restoring circuit for the iutch-seiccti rotary magnet 38 through the sequence s witch contact 1% anal the offnorinzil coutuc 59. The loteh-- selecting spindle will therefore be i'etiirnecl to its normal position Where, clue to the opening of the otl noriuul contacts 59, it will come to rciuy 139 suitch hook.

klicenergin more into circuit.

sing circuit at such The "on of this relay closes at the buck contact of its urnuiti'zz'e a circuit thro "l the sequence switch 3-01 '16 tor the o; inery sequence switch primary sequence su switch contact opci V 1; switch contacts 239 and ill) use a .1

removing theretnrtlution coil shunt around the condenser 2W- As the prinnrry s comes into its nineteenth po the sequence s "itch contacts 2oz? closed which places the buttery in trunk circuit to energize the iii :11 line re i's'i for purposes which will be hercinufttr described. As the primary sequence switch. comes into its twentieth position it opens the trunk circuit at the sequence switch contacts 223, 23%, 131 and It also ottime closes the sequence switch contacts s A anti By the closure oi? the sequence- SWi'tOl'i contact 226 a, circuit established for the carriage rotary insgnet 62 through. the buck contact and unnuturc cit test relay 261. it may be here observed that the test relays uiul were tleiincrgizeii the primary sequence snitch left its eenth position by the opeuiiur ofthe quence switch contacts 227 i i u J. the

in the twentieth position t l e i 1111 seouence switch no energizing circuit was closed. through these relays. in response to the one D nation of the carriage rotary 'ne" the brush carriage now returns to its gimlfllldl position, at which time circuit is closed from battery through. the sequence :switch contact 237 through the plate as, arm 72, contact spring 73, test relu-y' 261, sequence switch contact 297 to ground and. back to battery. The closure of this circuit causes the energilzution oi the test relay 261 which by the attraction of its armature opens the energizing circuit for the carriage rotary magnet 62 andv closes the circuit of the holct ing magnet 65 through the sequence switch contuct 223. In this manner the brush. cur-- riagjc is brought positively to a stop in its normal position.

The cncrgization of the test relay 261 has further. ore closed a circuit through its tln'lx'lt-lllt and front contact "for the primary sequence switch 201 which now moves out oi its twentieth position and comes to a stop in its first or DOLDll'ti position. In this move ment 0+ 'tlievpriinary sequence switch all of the apparatus associute with this sequence switch and this primaryselector is restored to its IlOllIlill condition uncl is rcutly to be operated in connection with u call from same line or u suos' outfrom cuuscs ii to is the 

